1. Field of the Invention
This invention relates, in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves poppet valves for subsea hydraulic couplings that open to allow flow of hydraulic fluid when the coupling members are connected together.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore, or receiving chamber, at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the larger bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore in the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members.
The male and female members of a hydraulic coupling each typically include a poppet valve slidably received within the bore of each member. Each poppet valve typically includes a conical valve face which seats, in the closed position, against a valve seat in the bore. The poppet valve opens to allow fluid flow, and closes the poppet valve face against the corresponding valve seat within the bore to arrest the flow. Generally the poppet valve is spring-biased to the closed position. The valve also includes a valve actuator which may be a nose or stem extending from the apex of the valve face along the longitudinal axis of the poppet valve. Contact between the valve actuators of the male and female member poppet valves forces each valve face away from the valve seat and into the open position for fluid flow between the members. Some undersea coupling members do not have valve actuators, but instead utilize valves that open in response to fluid pressure from the opposing coupling member.
In undersea applications, the male members and female members typically are attached to opposing manifold plates. Typically, between 10 and 30 coupling members may be attached to each manifold plate. It can be desirable to increase the number of coupling members attached to each manifold plate. The size of the manifold plate may be increased to accommodate additional coupling members. However, increasing the dimensions of a manifold plate to accommodate additional coupling members increases its weight and makes it more difficult for hoists, divers or remote operating vehicles to handle the manifold plates and engage the coupling members together, especially at subsea depths of several thousand feet or more. Alternatively, instead of increasing the manifold plate""s dimensions, each coupling member may be reduced in size (i.e., diameter). Reducing the diameter of coupling members, however, may also result in narrower flow passages and decreased wall thickness. If possible, it is desirable to reduce the diameter of coupling members without significantly or materially narrowing the flow passages or decreasing the wall thickness. Otherwise, couplings with narrower flow passages and decreased wall thickness may sacrifice performance and reliability, have lower flow rates, and increased risk of leaking hydraulic fluid into sensitive subsea environments.
Several patents of National Coupling Co., Inc. of Stafford, Texas disclose undersea hydraulic couplings having probe sections with reduced diameters, without sacrificing performance and reliability, and without increasing leakage risks. For example, U.S. Pat. No. 6,206,040 discloses an undersea hydraulic coupling having a stepped internal bore and a poppet valve positioned in the body section, rather than the probe section, of the male member. U.S. Pat. No. 6,085,785 discloses an undersea hydraulic coupling member with an extended probe section, and a poppet valve having an actuator that extends through the extended probe section. U.S. Pat. No. 6,283,444 discloses an undersea hydraulic coupling member with a poppet valve in the body section, and a valve actuator extending through the probe section and out from the leading face of the male coupling member. Similarly, U.S. Pat. No. 6,227,245 discloses an undersea hydraulic coupling member with a poppet valve in the body section, and a valve actuator extending through the probe section and out from the leading face of the male coupling member.
Most subsea coupling members have valve actuators that are less than one half the length of the poppet valve. The coupling members disclosed in the National Coupling patents identified above, however, have valve actuators that are greater than one half the length of the poppet valve, and may be one inch or more in length. These valve actuators extend at least partially through the internal bore in the probe section, and may or may not extend out from the leading face of the male coupling member in the normally closed position.
Hydraulic fluid in subsea hydraulic systems exerts high forces against the poppet valves in the coupling members, especially at higher flow rates and pressures. Valve actuators are especially vulnerable to the high hydraulic fluid forces. Valve actuators are subjected to the flow and turbulence of hydraulic fluid through the internal bore of each coupling member and at the junction where the coupling members are engaged together. Hydraulic fluid pressure and turbulence exerts lateral pressure against the valve actuators and may even bend, deflect, or laterally displace the valve actuators. Bent or deflected valve actuators may not properly contact each other to reliably open the poppet valves when undersea hydraulic coupling members are engaged together. Damaged valve actuators also can increase the risk of leakage or detrimentally affect the performance of the hydraulic system of which the coupling is a part.
The present invention resides in an undersea hydraulic coupling of the foregoing type having interlocking valve actuators. Valve actuators extending from each poppet valve come into contact to open the valves. The leading face of one valve actuator has a projection, and the leading face of the second valve actuator has a corresponding, mating recess. When the projection enters and engages the recess, the leading faces of the valve actuators interlock. The interlocked valve actuators better resist bending, deflection, or lateral displacement due to hydraulic fluid pressure and turbulence, thereby limiting or preventing damage to the actuators and hydraulic system.